/*
 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package java.beans;

import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.Map;

import static java.util.Locale.ENGLISH;

/**
 * A utility class which generates unique names for object instances.
 * The name will be a concatenation of the unqualified class name
 * and an instance number.
 * <p>
 * For example, if the first object instance javax.swing.JButton
 * is passed into <code>instanceName</code> then the returned
 * string identifier will be &quot;JButton0&quot;.
 *
 * @author Philip Milne
 */
class NameGenerator {

  private Map<Object, String> valueToName;
  private Map<String, Integer> nameToCount;

  public NameGenerator() {
    valueToName = new IdentityHashMap<>();
    nameToCount = new HashMap<>();
  }

  /**
   * Clears the name cache. Should be called to near the end of
   * the encoding cycle.
   */
  public void clear() {
    valueToName.clear();
    nameToCount.clear();
  }

  /**
   * Returns the root name of the class.
   */
  @SuppressWarnings("rawtypes")
  public static String unqualifiedClassName(Class type) {
    if (type.isArray()) {
      return unqualifiedClassName(type.getComponentType()) + "Array";
    }
    String name = type.getName();
    return name.substring(name.lastIndexOf('.') + 1);
  }

  /**
   * Returns a String which capitalizes the first letter of the string.
   */
  public static String capitalize(String name) {
    if (name == null || name.length() == 0) {
      return name;
    }
    return name.substring(0, 1).toUpperCase(ENGLISH) + name.substring(1);
  }

  /**
   * Returns a unique string which identifies the object instance.
   * Invocations are cached so that if an object has been previously
   * passed into this method then the same identifier is returned.
   *
   * @param instance object used to generate string
   * @return a unique string representing the object
   */
  public String instanceName(Object instance) {
    if (instance == null) {
      return "null";
    }
    if (instance instanceof Class) {
      return unqualifiedClassName((Class) instance);
    } else {
      String result = valueToName.get(instance);
      if (result != null) {
        return result;
      }
      Class<?> type = instance.getClass();
      String className = unqualifiedClassName(type);

      Integer size = nameToCount.get(className);
      int instanceNumber = (size == null) ? 0 : (size).intValue() + 1;
      nameToCount.put(className, new Integer(instanceNumber));

      result = className + instanceNumber;
      valueToName.put(instance, result);
      return result;
    }
  }
}
